But the implication that bonds will continue to rise in the future seems misguided.

Just for the record, I wasn't implying that. I'm relatively confident the S&P 500 will outperform 10-30 year U.S. Treasuries the next 10 years. I just thought it was an interesting stat that over basically the duration of someone's capital appreication years (30 years) bonds actually outperformed stocks.

Meanwhile the large deficits from most major governments probably means inflation and rising interest rates as soon as economies stabilize. That should drive bond prices down.

Should? I think Fed monetary actions the last 3-4 years juxtaposed against bond yields should cause someone to carefully reevaluate what they believe about the drivers of long-term interest rates. I think the Fed can pin long-term interest rates as low as they want for whatever length of time they think is good policy (financial repression).

Bottom line, I think bond prices are a bubble.

Perhaps semantics, but in my view bubbles are driven by greed and leverage. Bond prices are being driven by fears of deflation. Two completely different things, and in my mind when a "bubble" bursts you see a 60, 70, 80, 90% drop (think NASDAQ 2000-2002). You really think bond prices are going to drop that much?